Helical screw anchors are used extensively in construction to transfer loads from structures to the ground. The helical screw anchors must be installed parallel to the direction of pull or push from the load. Anchors are configured to auger into the ground providing a base for both compression and tension applications.
Loose to medium dense soils, fine to coarse sand and sandy gravel, as well as firm clay are the ground components that helical screw anchors are designed to auger through. Obstructions in the ground, such as a rock, can stress and shear the shaft or helix. With a conventional ground anchor, when hardpan such as bedrock or a large rock is encountered, it is necessary to pull out the anchor assembly. Assuming the anchor is not damaged, an attempt to drill to the correct depth from another point is performed.
In the event that a rock formation is quite large, moving the drilling location may not be a viable option. Another option could be predrilling a hole in the rock but in larger applications this would be costly and unfeasible.
Presently there lacks a helical screw anchors system that is effective in all underground applications. Even helical screw anchors with sharp curved leading edges are not suitable for cutting through solid rock. The edges easily become dull and therefore cannot auger through solid immovable rock.
U.S. Pat. No. 5,113,626 discloses an earth anchor apparatus having a hub with a longitudinal axis and first and second axial ends, and a load-bearing helix affixed to the hub. The load-bearing helix includes a generally radially extending leading edge adjacent to the first end of the hub, a generally radially extending trailing edge adjacent the second end of the hub, an inner circumferential section connected to the hub, and an outer circumferential section extending radially outward from the inner circumferential section and having an outer circumferential edge separated from the inner section.
U.S. Pat. No. 5,408,788 discloses a high strength cast screw having a hollow, installation wrench receiving hub, a helical, load bearing element projecting outwardly from the hub, and an elongated, pointed end spade integral with and extending away from the hub. The spade has two diametrically opposed, angularly disposed cutting margins located on opposite sides of the axis of the hub.
U.S. Pat. No. 5,213,448 discloses an anchor assembly having a support fastened to the foundation and a screw anchor installed in the earth in generally upright disposition with an upper end thereof located adjacent the foundation. The upper end is secured within a sleeve of the support assembly by a bonding composition to prevent movement of the screw anchor relative to the sleeve. During assembly of the apparatus, a lower bracket of the support assembly is attached to the foundation of the building to be stabilized, and the screw anchor is installed in the earth in a generally upright disposition with an upper end of a rod of the anchor located adjacent the lower bracket.
U.S. Pat. No. 8,079,781 discloses a support device in the form of a push pier capable of use in high load-bearing capacity applications involving significant lateral load conditions, the push pier having a lead section with a ground penetrating friction collar, and one or more extension members that are machine fabricated with an integrally formed hardened alloy steel coupling section that is adapted to mate with the push pier lead section or another similarly constructed extension shaft
U.S. Pat. No. 8,033,757 discloses a method and apparatus for placing a helical pile in the soil with minimal disturbances to the soil. The helical pile has an elongated pipe with a central chamber. The pipe has a helical blade with an opening in the trailing edge of the blade where grout is extruded. The grout fills those portions of the soil which were disturbed by the blade. Advantageously, those portions of the soil which were not disturbed by the blade are not infused with grout.
U.S. Pat. No. 7,736,095 discloses a conventionally available pile for civil engineering work is constructed such that the pile has in its inside a core body with wedges that stick into soil deep in the ground and function to prevent the pile from coming out of place.
U.S. Pat. No. 7,314,335 discloses an anchor pile apparatus has a helical anchor rotatable by a power source through an intermediate drive member. The drive member extends through a plurality of hollow pile sections, which are driven, one by one, into the soil following the penetration of the anchor. In one of the embodiments, the anchor and the pile sections are rotated separately by independent motors, thus expediting the installation of the pile in the pre-determined location.
U.S. Pat. No. 7,114,886 discloses a structural helical pile having an elongate shaft member a longitudinal axis. The structural helical pile also comprises a radially extending, generally helical load bearing member integral with the shaft member and projecting outwardly from the longitudinal axis of the shaft member. The helical load bearing member has a leading edge and a trailing edge. The respective leading and trailing edges intersect the shaft member in spaced relationship along the longitudinal length of the shaft member. The helical loadbearing member further comprises at least one rib integrally formed therein. In this aspect, each rib extends outwardly from the longitudinal axis of the shaft member and has a substantially uniform cross-sectional thickness.
U.S. Pat. No. 7,112,012 discloses an in-situ pile apparatus includes a helical anchor to which a plurality of elongated generally cylindrically shaped sections can be added. Each of the sections has a specially shaped end portion for connecting to another section. An internal drive is positioned in sections inside the bore of each of the connectable pile sections. The internal drive includes enlarged sections that fit at the joint between pile sections. In one embodiment, the internal drive can be removed to leave a rod behind that defines reinforcement for an added material such as concrete
U.S. Pat. No. 6,817,810 discloses a piercing device includes a shaft having interspaced threaded portions and unthreaded portions extending axially along at least a portion of its length. The unthreaded portions of the shaft are radially recessed with respect to the threaded portions. A helical plate with a threaded passageway can engage the threaded portions of the shaft at any desired location along the shaft. A key is then inserted into the passageway between the helical plate and an unthreaded portion of the shaft to hold the helical plate at the desired location on the shaft.
U.S. Pat. No. 6,871,455 discloses a reinforced ground anchor including a spike, a pressure cap having a planar surface, a rod having a drive section at one end, and a swivel connection connecting said pressure cap with the rod. An opening is formed in the pressure cap. A guide is located adjacent the opening. The pressure cap engages flush with the surface of the ground, due to the action of the swivel connection, when the rod is positioned in the ground soil and the spike passes through the opening to engage in the ground soil at an acute angle. The spike and the cap in combination with the rod provide the anchor with additional resistance against horizontal and vertical pressure.
U.S. Pat. No. 8,096,732 discloses methods and apparatus for foundation systems generally include a vertical support, a horizontal support configured to couple to the vertical support, and a composite material configured to couple to the horizontal support. The vertical support may be configured to resist fluctuation in soil elevation. The composite material may comprise a block material and a fibrous material.
U.S. Pat. No. 5,120,163 discloses an apparatus and method for stabilizing the foundation of an existing building structure which may or has experienced settlement or movement. A support for the foundation is provided that is adapted to be located at a position in underlying relationship to the foundation structure. A screw anchor having an anchor shaft and at least one helix thereon is driven into the ground adjacent the foundation support. An inverted U-shaped coupler adapted to be temporarily secured to the foundation support receives a jacking device there-within extending between the top of the coupler and the foundation support so that upon positioning of the support in supporting relationship to the foundation and insertion of the anchor into the ground.